Photographic compositions and processes-a

ABSTRACT

Photographic developing agents, which are lactone derivatives, such as coumarin derivatives and especially 6-hydroxy coumarin and 6-amino coumarin derivatives, and which have the property of forming a lactone developing agent precursor under neutral, slightly alkaline and acid conditions provide less stain without loss of desired sensitometric properties in photographic developer compositions, elements and processes. They are suitable in combination with other photographic developing agents. Corresponding lactone developing agent precursors are also especially useful.

United States Patent [72] Inventor Edwin N. Oftedahl, Jr.

Rochester, N.Y. [21] App]. No. 764,358 [22] Filed Oct. 1, 1968 [45]Patented Oct. 26, 1971 [73] Assignee Eastman Kodak Company Rochester,N.Y.

[54] PHOTOGRAPHIC COMPOSITIONS AND PROCESSES-A 16 Claims, No Drawings[52] U.S. Cl 96/66, 96/95 [51] Int. Cl G03c 5/30 [50] Field of Search96/29, 29 D, 76, 95, 63, 64,65, 66; 117/34 [56] References Cited UNITEDSTATES PATENTS 3,043,690 7/1962 Green et al. 96/29 3,061,434 10/1962Green et al. 96/76 X 3,232,758 2/1966 Holstead et al. 96/66 X 3,262,7817/1966 Ryan et al 96/76 2,603,659 7/1952 Raasch 96/66 X OTHER REFERENCESTreatment of black-and-white motion picture photomaterials, Khaikin etal., U.S.S.R. 150,009, 9-14-62, Chemical Abstract, Vol. 58, p. 4086c.

Primary Examiner-William D. Martin Assistant Examiner-Theodore G. DavisAttorneys-R. E. Knapp, B, D. Wiese and W. H. J. Kline ABSTRACT:Photographic developing agents, which are lactone derivatives, such ascoumarin derivatives and especially 6-hydroxy coumarin and 6-aminocoumarin derivatives, and which have the property of forming a lactonedeveloping agent precursor under neutral, slightly alkaline and acidconditions provide less stain without loss of desired sensitometricproperties in photographic developer compositions. elements andprocesses. They are suitable in combination with other photographicdeveloping agents. Corresponding lactone developing agent precursors arealso especially useful.

PHOTOGRAPI'IIC COMPOSITIONS AND PROCESSES-A BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates tophotographic elements, processing compositions, especially developercompositions, and developing processes. In one aspect this inventionrelates to photographic elements, processing compositions and processesutilizing a photographic silver salt developing agent which has theproperty of forming a developing agent precursor under certainconditions. Another aspect relates to photographic elements, processingcompositions and processes utilizing such a developing agent precursor.

2. The Prior Art It is well known to employ silver halide developingagents in processing photographic silver salt emulsions. It is also wellknown to incorporate silver salt developing agents into a layer of aphotographic element containing a layer of a photosensitive silver salt.Typically, such emulsions are developed after exposure by treating themwith a development activator, e.g., in a alkaline solution. Frequently,the alkaline solution will also contain a developing agent. Followingdevelopment by either system, the developed silver image can be fixed orstabilized, for example, by treating the developed silver salt layer ina conventional fixing bath, such as a sodium thiosulfate or thiocyanatebath. The developed or fixed photographic silver salt layer can then bewashed and dried.

Although use of a developing agent in a layer of a photographic elementis convenient, it is frequently disadvantageous because theconcentration of developing agent in the coating can be greatly reducedon storage for one or more reasons such as diffusion, sublimation, andthe like. Also, the developing agent can become oxidized, and thusrendered ineffective, after relatively short period of storage. One ofthe methods proposed to overcome this problem is to incorporate aso-called developing agent precursor or blocked developing agent in oneof the layers of the photographic element. These developing agentprecursors are compounds which upon contact with a suitable activatingagent form a silver halide developing agent. However, the developingagent precursors of the prior art also are not entirely successful andfrequently are unable to form the desired developing agent within asuitable time period and/or form undesirable by-products which adverselyaffect the developing process. Further many of the better developingagents of the prior art in terms of speed and density rapidly oxidize toproduce unsightly and objectionable black oxidation products which causeundesired stain.

There has accordingly been a need for developing agents and/or so-calleddeveloping agent precursors or blocked developing agents which providereduced stain while maintaining or providing improved photographicspeed, density and other desired sensitometric properties.

There has also been a need for developing agents and/or developing agentprecursors which are acid quenchable. Developing agents and/ordeveloping agent precursors which are acid quenchable include suchcompounds which have the property of providing desired developing actionin the presence of a development activator and, when the desired degreeof development is reached, such developing action can be stopped bylowering the pH and thus quenching the developing action by convertingthe developing agent to a developing agent precursor form. Developingagents which are acid quenchable and which have a ring closure mechanismto form a developing agent precursor have not been previously known.

While the synthesis and chemistry of lactone compounds which have a ringopening and closure mechanism under respectively alkaline and acidconditions are known, no lactones have been reported in photographicelements, compositions and/or processes as developing agent precursors.For example, the synthesis and chemistry of coumarins is described forinstance by S. M. Sethma and N. M. Shah, Chemical Reviews,36, l, (I945);R. C. Elderfield, Hererocyclic Compounds, Volume 2, pages 173-216(1951); and by R. Adams, Organic Reactions, Volume VII, pages l-58(1953). Coumarin is known to form cinnamic acid salts under alkalineconditions. These compounds have not been employed heretofore inphotographic elements or in developer compositions as a so-calledblocked developing agent or developing agent precursor. Coumarin, forexample, is not a suitable developing agent. The use of a 7,8-dihydroxycoumarin as a developing agent per se is described in U.S.S.R. Pat. No.150,009 issued Sept. 16, 1962, (Chemical Abstracts, Volume 58, P4086e).British Pat. No. 767,70l Kodak discloses a 3- pyrazolidone developingagent with certain developing agents including 3,4-dihydroxycoumarinwhich like 7,8-dihydroxy coumarin has an ene-diol structure. There is norecognition nor suggestion in the art that a coumarin having hydroxy oramino in the 6 and/or 8 position would form a developing agent, nor isany indication given that such a coumarin compound can be employed as anincorporated developing agent or developing agent precursor.

Coumarin compounds have also been employed in photographic emulsions assensitizers such as disclosed in French Pat. No. 1,349,658. However,such compounds are not developing agents or developing agent precursors.

Accordingly, it is an object of the invention to provide improvedphotographic elements containing an incorporated developing agent ordeveloping agent precursor providing reduced stain while maintainingdesired sensitometric properties.

Another object is to provide improved processing compositions,especially developer'compositions, and emulsions for photographicelements, such compositions containing a developing agent or developingagent precursor providing reduced stain while maintaining desiredsensitometric properties.

A further object is to provide an improved method of developing a latentimage in a photographic silver salt layer employing a lactone derivativesilverhalide developing agent or developing agent precursor.

SUMMARY OF THE INVENTION According to the invention reduced stainwithout loss of desired sensitometric properties is provided inphotographic elements, processing compositions, especially developercompositions, and processes by employing a lactone derivative silverhalide developing agent which has the property of forming a lactonedeveloping agent precursor under neutral, slightly alkaline and acidconditions, e.g., a pH about 9 or below and/or a lactone silver halidedeveloping agent precursor which has the property of forming a lactonederivative silver halide developing agent in the presence of an alkalinedevelopment activator. Especially suitable photographic elements,processing compositions and processes according to the invention arethose employing a. a described lactone derivative photographic silverhalide developing agent such as a hydroxy cinnamic acid and/or an aminocinnamic acid, i.e., coumarin derivative, mixtures thereof, and theirsalts, e.g., their acid salts such as their chloride, hydrochloride, andsulfate salts, alkali metal salts, such as sodium or potassium and/or b.a hydroxy coumarin and/or amino coumarin developing agent precursor,especially a 6-hydroxy coumarin and/or 6- amino coumarin developingagent precursor, mixtures thereof and their salts, as described,

DESCRIPTION OF THE PREFERRED EMBODIMENTS A wide range of lactonederivative silver halide developing agents which have the property offorming a lactone develop ing agent precursor under neutral and acidconditions can be employed according to the invention. These include anylactone derivatives which provide desired developing activity andreduction of stain without adversely affecting desired maximum density,minimum density, photographic speed and other desired sensitometricproperties. Suitable lactone derivative developing agents include thosewhich under neutral, slightly alkaline or acid conditions, i.e., whenthe pH is lowered to a level of about 9 or lower, i.e., about 2 to about9, do not have significant developing activity, if any, due to formationofa developing agent precursor.

The mechanism involved is believed to involve the opening and closing ofan anhydro ring in lactone compounds depending on pH conditions. Forinstance, in the case of a 6-hydroxy coumarin and/or 6-amino coumarindeveloping agent precursor, under alkaline conditions such as a pH ofabout to about 14, the anhydro ring of such a lactone is believed toopen forming a cinnamic acid developing agent, i.e., a coumarinderivative developing agent. This cinnamic acid developing agent hasgood developing properties.

A wide variety of hydroxy cinnamic acid and/or amino cinnamic aciddeveloping agents can be employed according to to the invention.Suitable hydroxy cinnamic acid or amino cinnamic acid developing agentsinclude any such compounds which cause reduction of a photographicsilver salt in exposed areas of a layer containing such photographicsilver salt without adversely affecting the unexposed areas of thephotosensitive silver salt. Especially suitable developing agents arederivatives of 6-hydroxy coumarins, 6-amino coumarins, mixtures thereof,and their salts. Suitable cinnamic acid developing agents of theinvention include compounds of the formula:

a. R and R are individually hydrogen, halogen, e.g., chlorine, bromineor iodine, or alkyl, e.g., alkyl containing one to five carbon atomssuch as methyl, ethyl, propyl, butyl and pentyl,

b. R and R are individually hydrogen, alkyl, e.g., alkyl containing oneto eight carbon atoms such as methyl, ethyl, propyl, butyl and pentyl,alkoxy, e.g., alkoxy containing one to five carbon atoms such asmethoxy, ethoxy, propoxy, butoxy and pentoxy, halogen, as described, andaryl, e.g., aryl containing up to 20 carbon atoms, such as phenyl, tolyland xylyl,

c. R, and R are individually hydrogen, hydroxy, amino, i.e., NH NHR or-NRR wherein R and R are alkyl containing one to five carbon atoms, suchas methyl, ethyl, propyl, butyl and pentyl; alkyl containing one to fivecarbon atoms, as described, alkoxy containing one to five carbon atoms,as described, aryl, e.g., aryl containing up to 20 carbon atoms such asphenyl, tolyl and xylyl,

mixtures thereof, and their salts, e.g., acid salts such as chloride,hydrochloride and sulfate salts, or alkali metal salts, and wherein atleast one of R and R is hydroxy or amino.

Esters such as alkyl esters containing one to five carbon atoms,typically a methyl ester, ethyl ester, propyl ester, or butyl ester ofthe described cinnamic acid compounds, e.g., those within structure l,are also developing agents. However, if an ester of a compound ofstructure I is formed this can hinder or prevent the formation of adeveloping agent precursor as described. Accordingly, in some cases itcan be undesirable to include compounds in a photographic element,composition or process accordingly to the invention which causeformation of esters, typically alkyl esters of the described cinnamicacid developing agents.

Suitable cinnamic acid developing agents include:

[3,4-dimethyl-2,5-dihydroxy cinnamic acid;

4-methyl-2,5-dihydroxy cinnamic acid;

6-bromo-4-methyl-2,S-dihydroxy cinnamic acid; 2-hydroxy-5-amino cinnamicacid;

wherein R,, R R R R and R are described for structure I. Examples ofdeveloping agents within structure ll include:

- CH:C 0 OH IIO- CHz-COOH s 2)1- -OH and CI'Ir-C O OII Also included arecompounds which are derivatives of 3,4- dihydrocoumarins. These includecompounds of the formula:

(III) l 1: 1 R4- -C-C=COOII Rs OH wherein R R R R R and R are asdescribed for Structure 1. Examples of compounds within Structure l Ilinclude:

Also a wide range of lactone silver halide developing agent precursorscan be employed which have the property of forming a lactone derivativesilver halide developing agent in the presence of an alkalinedevelopment activator, e.g., under a1 kaline conditions including a pHof about 8 to 14, typically a 5 pH of about 10-14, preferably a pH ofabout 12 to about 14. Suitable lactone developing agent precursorsinclude any lactones which in the presence of an alkaline developmentactivator have the property of forming a lactone derivative silverhalide developing agent, typically, it is believed, by opening of theanhydro ring of the lactone, and in the presence of such a developmentactivator provide desired developing activity and reduction of stainwithout adversely affecting desired maximum density, minimum density,photographic speed and other desired sensitometric properties.

Suitable hydroxy coumarins and amino coumarins which are developingagent precursors according to the invention include developing agentprecursors of the formula:

(IV) R:

wherein R,, R R R R and R,, are as described for strucwherein R R R R Rand R,, are as described for structure I, with the exception that R canalso be aryl, as described, especially phenyl, tolyl or xylyl. Examplesof developing agent precursors within structure V include:

clude 3,4-dihydrocoumarin developing agent precursors corresponding tothe coumarin developing agent precursors of structure 1V. Examples of3,4-dihydrocoumarin developing agent precursors include:

6,7-dihydroxy-4-methyl-3,4-dihydrocoumarin and7,8-dihydroxy-4-methyl-3,4-dihydrocoumarin.

The developing agents and/or developing agent precursors of theinvention are suitable in a range of physical locations in aphotographic system. They can be employed in one or more layers of aphotographic element and/or in a processing composition if desired. Forexample, they can be employed in developer compositions, such as anaqueous alkaline developer solution, or can be incorporated into alayer, such as a silver halide emulsion layer, or overcoat layer of aphotographic element. They can be employed, as described, for example,in copending U.S. Pat. application, Ser. No. 764,301 of Oftedahl, filedOct. 1, 1968, titled Photographic Compositions and Processes (8)" inelements, e.g., photographic elements and/or image receivers and/orprocessing compositions, e.g., developer compositions intended for usein diffusion transfer processes. Diffusion transfer processes andphotographic elements in which the developing agents and/or developingagent precursors are useful as described, for example, in U.S. Pat. Nos.2,352,014 of Rott issued June 20, 1944', 2,543,181 of Land issued Feb.27, 1951; and 3,337,342 of Green issued Aug. 22, 1967. They can be usedalso in socalled high-speed diffusion transfer processes as described,for example, in U.S. Pat. No. 3,326,683 of Land et al. issued June 20,1967; or in other types ofdiffusion transfer processes such as thosedescribed in U.S. Pat, Nos. 2,857,274 of Land et al. issued Oct. 21,1958; 3,020,155 of Yackel et al. issued Feb. 6, 1962; 2,584,030 of Landissued Jan. 29, 1952; and 2,923,623 ofLand issued Feb. 2, 1960.

An alkaline development activator can be employed to activate thedeveloping agents and/or developing agent precursors of the inventionwhich provides the desired pH. These include those commonly employed inthe photographic art as development activators, such as inorganicalkalies, e.g., alkali metal hydroxides including sodium hydroxide,potassium hydroxide and lithium hydroxide, alkali metal carbonates, suchas sodium carbonate, sodium bicarbonate and the like, as well as organicalkalies such as organic amines and aminoalkanols, e.g., ethanolamineand iminodiethanolamine or morpholine. The concentration of developmentactivator suitable will vary depending on the various components of thesystem, the photographic emulsion employed, the desired image, and thelike. A concentration is usually employed which provides a pH of atleast about 10, typically about 10 to about 14 and preferably about 12to about 14. Upon treatment with an alkaline activator, it is believedthe lactone ring of the described coumarin compounds, for example, opensto yield a hydroxy group and thus a strong developer. The developingaction can be stopped, or returned to its initial precursor form byreturning the developing agent form, for example, to the developingagent precursor form by treatment with an acid, e.g., usually a mildacidic solution such as an aqueous acetic acid, carbonic acid,hydrochloric acid, boric acid or nitric acid solution. This property isreferred to as acid quenching and is especially useful in photographicprocesses where residual oxidation or developer activity is undesirable.The foregoing relationship or reaction can be illustrated by thefollowing equation employing coumarins as an example:

coumarin form cinnamic acid form Developer precursor Developing agentwherein R,, R R R R and R are as described for structure I.

In order to obtain the desired developing action upon conversion to thecinnamic form the coumarin preferably has a hydroxy group or an aminogroup or a derivative of these groups which is in the 6 position (i.e.,R and/or 8 position (i.e., R This hydroxy or amino group is para orortho in the cinnamic form, to the unblocked hydroxy group.

The lactone derivative developing agents and lactone developing agentprecursors, e.g., coumarins or cinnamic acid compounds used in thepractice of the invention, can be prepared by conventional methods knownto the art or by obvious modifications of such methods to obtainderivative or substituted products. Various methods for preparing agiven coumarin, as described, can, for example, be obtained from thefollowing sources: 7-methyl-6-hydroxy coumarin-Desni and Mavani, Proc.Indian Acad. Sci., 25A, 327 (1947); 4,7- dimethy-6-hydroxycoumarin-Desni and Mavani, Proc. Indian Acad. Sci., 15A, ll (1942); and6-amino coumarinG. Morgan, J. Chem. 806., Transactions 85, l233 1904).Further preparations can be obtained from the prior art and also fromthe described references.

The described hydroxy cinnamic acids and/or amino cinnamic acids andtheir salts can be prepared by known processes or, as in the practice ofthe invention, by the alkalation of the respective coumarin.

The described developing agents and developing agent precursorsaccording to the invention can be employed in one or more layers of aphotographic element. Accordingly, one embodiment of the inventioncomprises in an element comprising a support containing at least onelayer comprising a photographic silver halide developing component theimprovement comprising a lactone derivative photographic silver halidedeveloping agent which has the property of forming a lactone developingagent precursor under neutral and acid conditions. The lactonederivative developing agent is typically selected from coumarinderivatives, mixtures thereof and their salts, especially, derivativesof 6-hydroxy coumarins, 6-amino coumarins mixtures thereof, and theirsalts. These compounds can be employed in a photographic silver saltemulsion layer, an overcoat layer, a layer under the emulsion layer, abaryta layer, an antihalation layer, or virtually any layer contiguousto the silver salt to be developed. For instance, the developing agentsand developing agent precursors of the invention can be employed in aphotographic element having a layer containing:

a. a silver halide developing agent which is a hydroxy cinnamic acidand/or an amino cinnamic acid, and/or b. a sliver halide developingagent precursor which is a hydroxy coumarin and/or an amino coumarin,and a photographic silver salt layer.

Another embodiment of the invention comprises in an element comprising asupport having at least one layer comprising a photographic silverhalide developing component the improvement comprising a lactone silverhalide developing agent precursor which has the property of forming alactone derivative silver halide developing agent in the presence of analkaline development activator. Such an element typically contains adeveloping agent precursor, as described, selected from the groupconsisting of 6-hydroxy coumarin and 6-amino coumarin developing agentprecursors, mixtures thereof, and their salts.

The developing agents and/or developing agent precursors described canbe employed for developing an image in a wide range of photographicemulsions in photographic systems.

The photographic emulsions employed can be X-ray or other nonspectrallysensitized emulsions or they can contain spectral-sensitizing dyes suchas described in US Pat. Nos. 2,526,632 and 2,503,776. Spectralsensitizers which can be used include cyanines, merocyanines, styrylsand hemicyanines.

Various photographic silver salts can be used in the practice of theinvention. These include photographic silver halides such as silveriodide, silver bromide, silver chloride, as well as mixed halides suchas silver bromoiodide, silver chloroiodide and the like. Photographicsilver salts which are not silver halides can also be employed such assilver salts of certain organic acids.

Photographic coatings which are suitable can be coated on a wide varietyof supports. Suitable supports include those generally employed forphotographic elements, such as, for example, cellulose acetate films,cellulose nitrate films, polyethylene terephthanlate films, or otherpolyester films, polycarbonate films and related films or resinousmaterials; as well as papers, such as paper supports coated withresinous materials, e.g., coated with polyethylene, polypropylene and/orethylene-butene copolymers; glass; metal, and the like. The supports orlayers coated on them can contain fluorescent-brightening agents such asstilbenes, benzothiazoles and benzoxazoles. Some of the coumarincompounds described can also act as brightening agents.

The photographic elements processed according to the invention typicallycontain an emulsion layer comprising any of the known binding materialssuitable for photographic purposes. These include natural and syntheticbinding materials generally employed for this purpose, for example,gelatin, colloidal albumin, water soluble vinyl polymers, such as monoand polysaccharides, cellulose derivatives, proteins, water solublepolyacryl amides, polyvinyl pyrrolidone and the like, as well asmixtures of such binding agents. These binding materials can includewater insoluble polymers such as polymers of alkyl acrylates andmethacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates andthe like. The elements can also contain stripping layers and/orantistatic layers (i.e., conducting layers).

The developing agents and/or developing agent precursors of theinvention can be employed in combination with addenda known in the artto be useful in and/or for processing photographic elements. Forinstance, the photographic emulsions and compositions of the inventioncan contain various photographic addenda, particularly those known to bebeneficial in photographic compositions. The various addenda andconcentrations to be employed can be determined by those skilled in theart. Suitable photographic addenda include hardeners, e.g., those setforth in British Pat. No. 974,317; buffers which maintain the desireddeveloping activity and/or pl-l level, coating aids, plasticizers, speedincreasing addenda, such as amines, quaternary ammonium salts, sulfoniumsalts, and alkylene oxide polymers; and various stabilizing agents, suchas sodium sulfite. The photographic silver salt emulsions of theinvention can also be chemically sensitized with compounds of the sulfurgroup such as sulfur, selenium and tellurium sensitizers, noble metalsalts such as gold, or reduction sensitized with reducing agents orcombinations of such materials.

Developing agents and developing agent precursors as described can alsobe used in layers of photographic elements or processing solutionsintended for use in monobath processing such as described in U.S. Pat.No. 2,875,048 of Haist et al. issued Feb. 24, 1959, and British Pat. No.1,063,844 of Beavers et al. issued Mar. 30, 1967, and in webtypeprocessing, such as described in U.S. Pat. No. 3,l79,5 l7 ofTregillus etal. issued Apr. 20, 1965.

The developing agents and developing agent precursors of the inventioncan be employed in photographic elements designed for processing instabilization type processing. For example, they can be incorporated inone or more layers of a photographic element which is exposed, activatedby contact with alkaline activator, and then contacted with athiocyanate or thiosulfate solution, such as ammonium thiocyanate, orthey can be incorporated in the alkaline activator. Such processes aredescribed, for example, in U.S. Pat. No. 3,326,864 of Nishio issued June20, I967; British Pat. No. 1,004,302; French Pat. No. 1,516,556 ofFassbender; and in an article by H. D. Russell E. C. Yackel and E. G.Grouse in the PSA JOURNAL, Aug., 1950, pages 59-62, entitledStabilization Processing of Films and Papers."

The developing agents and developing agent precursors employed accordingto the invention can also be present in one or more layers of aphotographic element designed for recording color images and/or inprocessing compositions employed with such elements. For example, thesecompounds can be employed in one or more layers of a photographicelement containing a photographic layer sensitive to the blue region ofthe spectrum, a photographic layer sensitive to the green region of thespectrum, and a photographic layer sensitive to the red region of thespectrum. The layers sensitive to the blue, green and red regions of thespectrum can contain any suitable sensitizing dyes. Photographicelements designed for recording color images in which and/or for whichthe developing agents and developing agent precursors of the inventionare useful are described, for example, in Mees, The Theory of thePhotographic Process, 3rd Edition, pages 382-396.

A photographic element and/or processing composition according to theinvention can also contain toning agents such as, for example,polyvalent inorganic salts of the type described in U.S. Pat. No.2,698,236 of Land issued Dec. 28, 1954; silica as described in U.S. Pat.No. 2,698,237 of Land issued Dec. 28, 1954; and heterocyclic mercaptanssuch as the mercapto azoles, e.g., mercapto diazoles, mercapto triazolesand mercapto tetrazoles.

The developing agents and/or developing agent precursors of theinvention can be employed in combination with any silver halidedeveloping agent. The developing agents and/or developing agentprecursors of the invention can be employed in such combinations asauxiliary developing agents or as the main components of the developercombination and/or developing agent precursor combination. Suitablesilver halide developing agents which can be employed with thedeveloping agent or developing agent precursor of the invention include,for example, polyhydroxybenzenes, such as hydroquinone developingagents, e.g., hydroquinone, alkyl substituted hydroquinones, such ast-butyl hydroquinone, methyl hydroquinone and 2,5-dimethylhydroquinone;catechol and pyrogallol; chloro substituted hydroquinones such aschlorohydroquinone or dichlorohydroquinone; alkoxy substitutedhydroquinones such as methoxy hydroquinone or ethoxy hydroquinone;aminophenol developing agents, such. as 2,4-diaminophenols, e.g.,2,4-diamino-6-methyl phenol, and methylaminophenols; ascorbic acid,ascorbic acid ketols, such as those described in Green U.S. Pat. No.3,337,342 issued Aug. 22, 1967; hydroxylamines such asN,N-di(2-ethoxyethyl)amine, 3-pyrazolidone developing agents such aslphenyl-3-pyrazolidone, including those described in British Pat. No.930,572; and acyl derivatives of p-aminophenol such as described inBritish Pat. No. 1,045,303. Such developing agents can be used alone orin a combination when used with the developing agents or developingagent precursors of the invention.

The developing agents and/or developing agent precursors of theinvention can be used in combination, for example, with one or more ofthe following compounds:

l-phenyl-3-pyrazolidone hydroquinone methyl hydroquinone 2,5-dimethylhydroquinone 2,6-dimethyl hydroquinone tertiary butyl hydroquinone3,6-dihydroxy benzonorbornane 2,4-diamino-6-methyl phenoldihydrochloride 4-phenyl catechol tertiary butyl pyrocatechol2,4-diaminophenol dihydrochloride ascorbic acid N-methyl-p-aminophenolsulfate N,N-ethylene di(oxymethyl)pyridinum perchlorate 2-(3-sulfopropyl)-2-thiopseudo urea7,-14-diaza-6,lS-dipxoeicosane-l,ZI-bis-(pryidinium perchlorate) Thesecompounds, for instance can be incorporated in a photographic elementemployed in a diffusion-transfer system, which after exposure can bedeveloped employing a developer composition containing a developingagent and/or developing agent precursor of the invention.

One or more of the described combination of compounds can be in aphotographic element and/or processing composition, e.g., developercomposition of the invention. For example, a photographic element cancontain a 3-pyrazolidone developing agent, such asl-phenyl-3-pyrazolidone and/or lphenyl-4,4-dimethyl-3-pyrazolidone,and/or a 2,4- diaminophenol developing agent, such as 2,4-diamino-6-methylphenol and/or 2,4-diamino-6-methoxyphenol, and be developedemploying a developer composition containing a developing agent and/ordeveloping agent precursor of the invention, e.g., a 6-amino coumarinand/or 6-hydroxy coumarin, as described, such as4,7-dimethyl-6-hydroxycoumarin.

The developing agents and developing agent precursors of the inventioncan be employed in processing compositions in any form suitable fordeveloping an exposed photographic element. For example, they can beemployed as mixtures such as mixtures of the developing agents and/ordeveloping agent precursors of the invention as auxiliary developerswith other developing agents. They can be supplied as an aqueous silverhalide developer solution or liquid concentrate; as a component of asolid particulate composition suitable for dissolving in a solvent suchas an aqueous solvent; as a viscous composition containing variousthickening agents; as a packaged component of a kit for mixing withvarious processing agents or as a component of a fusible solid such as asolid containing a homogeneous of an alkaline oxide polymer and adeveloping agent precursor of the invention which melts above about roomtemperature, and the like.

Another embodiment of the invention is in a photographic processingcomposition comprising a silver halide developing component and analkaline development activator the improvement comprising a lactonederivative silver halide developing agent which has the property offorming a lactone developing agent precursor under neutral, slightlyalkaline and acid conditions.

A photographic processing composition includes any compositions commonlyemployed for processing photographic elements, such as developercompositions, e.g., developer solutions or solid particulatecompositions suitable for dissolving in a suitable solvent such aswater, ethanol, ethylene glycol and the like, stabilizer compositions,monobaths, activator compositions, hardener compositions and the like.

A typical composition according to this embodiment is a developercomposition comprising a silver halide developing component, which is ahydroxy cinnamic acid and/or amino cinnamic acid'developing agent, e.g.,within structure I, mixtures thereof and their salts; and/or a 6-hydroxyand/or 6- amino coumarin developing agent precursor, as described, e.g.,within structure IV, mixtures thereof and their salts.

A composition according to the invention can contain a silver halidesolvent. A wide range of silver halide solvents are suitable, such asalkali metal and ammonium thiocyanates, e.g., sodium and potassiumthiocyanate and ammonium thiocyanate, alkali metal thiosulfates, such assodium thiosulfate and potassium thiosulfate, thiourea compounds, andthe like.

A further embodiment of the invention is in a photographic processingcomposition, typically a developer precursor composition, comprising asilver halide developing agent precursor the improvement comprising alactone silver halide developing agent precursor, as described, whichhas the property of forming a silver halide developing agent in thepresence of an alkaline de\ elopment activator.

A further embodiment of the invention is in a photographic process fordeveloping a latent image in a photographic silver salt layer of aphotographic element wherein the silver salt layer is contacted with adeveloping component in the presence of an alkaline developmentactivator the improvement wherein the developing component comprises alactone silver halide developing agent precursor which has the propertyof forming a lactone derivative silver halide developing agent in thepresence of the alkaline development activator.

According to this embodiment, the invention can comprise a process ofdeveloping a latent image in a photographic silver salt layer bycontacting the silver salt layer with a processing compositioncontaining a silver halide solvent and a silver halide developing agentprecursor, as described, such as a hydroxy coumarin and/or an aminocoumarin developing agent precursor.

The process according to this embodiment can also employ another silverhalide developing agent, as described, either as the main developingagent or as an auxiliary developing agent in a layer of a photographicelement processed and/or in the silver halide developing precursorcomposition. Developing action, which is effected upon contact of thedeveloping agent precursor with a suitable activator, can be stopped bymerely lowering the pH in the vicinity of the developing agent and thusreturning the developing agent to its precursor form. Suitableactivators which can be used include those described, and especiallythose which yield a pH of about 10.0 or greater.

Another embodiment of the invention is in a photographic processcomprising developing a latent image in a photographic silver salt layerof a photographic element employing a silver halide developing agent inthe presence of an alkaline development activator the improvementcomprising developing said latent image with a lactone derivative silverhalide developing agent, as described, which has the property of forminga lactone developing agent precursor under neutral and acid conditions.

According to this embodiment a process is provided for developing alatent image in a photographic silver salt layer of a photographicelement by contacting the silver salt layer with a developing agentwhich is, for example, a cinnamic acid developing agent, as described,i.e., a derivative ofa coumarin developing agent precursor, asdescribed, in the presence of an alkaline development activator.

Further development or oxidation can then be stopped, thus preventing orsubstantially reducing developer stain, by lowering the pH of thedeveloper to a neutral, slightly alkaline or acid condition, i.e., belowabout 9. As described, the lowering of the pH causes the hydroxycinnamic acid and/or amino cinnamic acid, for example, to form itsrespective coumarin form which has only weak, and usually negligibledeveloping activity, if any.

The activating pH according to this process should range from about to14 and best results are obtained when the pH is above about 12. Thequenching pH range should be about from about 9 to 2. The optimum pH forany system will in many cases also be influenced by the photographicelement, the desired image, the various addenda used in the developer,emulsion or layers, etc.

The concentrations .of the developing agents and/or developing agentprecursors used in the practice of the invention can vary over wideranges depending upon the particular photographic and physical variablepresent in the system, for example, the position of the developing agentand/or developing agent precursors in the photographic element, thedeveloper composition, the desired image, etc. Suitable concentrationsare also dependent on processing conditions, ad-

' denda present in the photographic element to be processed and/or inthe processing compositions. Suitable optimum concentrations can easilybe determined by those skilled in the art through routineexperimentation. Typically, when a developing agent according to theinvention is employed in a photographic element, it is employed in theconcentration of about 0.01 to about 5 moles of developing agent permole of silver present in the photographic element. When a developingagent precursor is employed in a photographic element, it is typicallyemployed in a concentration which provides about 0.01 to about 5 molesof developing agent per mole of silver present in the photographicelement upon activation. Usually about 0.01 to about 5 moles ofdeveloping agent precursor per mole of silver present is sufficient.When a developing agent and/or developing agent precursor composition,as described, is employed to process a photographic element, the totalconcentration of developing agents and precursors is typically about0.0l to about l0, e.g. l to 5, percent by weight of the total developercomposition. The particular developing time required can vary over awide range between a few seconds up to an hour or more, depending on thedesired image, and the various addenda etc. present; optimum developingtime can also, however, be obtained by routine experimentation.

It is often advantageous to have an antifoggant present in the developercompositions of the invention and/or in the photographic elementprocessed according to the invention. Suitable antifoggants includeorganic antifoggants, such as benzotriazole, benzimidazole,Z-mercaptobenzimidazole, nitroindazole, and mer'captotetrazoleantifoggants. The developer compositions of the invention can contain aninorganic antifoggant, such as potassium bromide, potassium iodideand/or sodium bromide. The concentration of antifoggant in either thedeveloper composition or element can be varied depending upon thedesired image, other components present, subsequent processing steps andthe like. The developer typically contains less than about 2 percent byweight of the antifoggant and usually in the range of about 0.01 to 2percent by weight. Copending U.S. Pat. application, Ser. No. 764,30! ofOftedahl, filed Oct. 1, 1968, titled Photographic Compositions andProcesses (B)" sets out use of developing agents and/or developing agentprecursors, described herein, especially 6-hydroxy coumarins and/or 6-amino coumarins, with photographic diffusion transfer systems. Thedisclosure in this application is incorporated herein by reference. Itwill be appreciated that the requirements for developing agents and/ordeveloping agent precursors in diffusion transfer systems set out inthat application are very stringent compared to photographic systems ingeneral.

A further understanding of the invention can be had from the followingexamples.

EXAMPLE 1 This example illustrates a photographic element comprising anincorporated developing composition according to the invention.

In this example an initial coating is prepared by admixing an aqueoussolution containing 2 ml. of IO percent (wt.) saponin; 4ml. of aqueoussodium bisulfate solution (I mg./ml.); 17 ml. of methanol containingone-quarter ml. of dimethylacetamide; 640 mg. of 7-methyl-6-hydroxycoumarin, and 0.8 ml. of 10 percent (wt.) formaldehyde to 26 g. of 10percent (wt.) gelatin. The admixture is then coated on a celluloseacetate film support at a coverage of 500 mg. gelatin/ft. and dried. Asilver halide emulsion mixture is prepared by admixing 13 ml. of asilver chlorobromide emulsion, 2 ml. of 10 percent (wt.) saponin, l5 g.of 10 percent (wt.) gelatin, 1.2 ml. of aqueous sodium bisulfitesolution (1 mg./ml.), 200 mg. of 7-methyl-6- hydroxy coumarin dissolvedin 18.5 ml. of methanol containing one-quarter ml. of dimethylacetamide,and 0.6 ml. of i percent (wt.) formaldehyde. The emulsion mixture isthen coated over the dried initial coating at a silver coverage of about190 mg. Ag./ft. and dried.

The coating is exposed through a step wedge and processed by bathing for2 minutes on an alkaline activator, consisting of an aqueous sodiumhydroxide solution having a pH of 12 to 14, stopped, fixed and washed.17 steps are visible on the layer after it is processed.

EXAMPLE 2 This example illustrates a developer composition anddeveloping process according to the invention.

. In this example a developer solution, designated as developer solution(A), is prepared by dissolving g. of 6- amino coumarin, 50 g. of sodiumhydroxide, and l g. of Na,. SO in sufficient distilled water to provide1 liter of solution.

A 12 inchX35 mm. strip of a paper support coated with a silverchlorobromide gelatin emulsion is exposed sensitometrically for 1second. The exposed strip is then processed for 2 minutes in thedescribed developer solution (A).

steps are visible on the emulsion layer. The resulting minimum densityis 0.04, maximum density is 0.26, and gamma is 0.20. The element is freeof stain.

EXAMPLE 3 This is a comparative example.

The process of example 2 is repeated with the exception that thedeveloper solution contains 5 g. of 6,7-dihydroxy-4- methyl coumarin inplace of 6-amino coumarin.

An exposed emulsion as set out in example 2 is developed by contactingit with the developer solution.

13 steps are visible in the developed image. The resulting minimumdensity is 0.03, maximum density is 0.30 and gamma is 0.20.

This example illustrates that the 6-amino coumarin of example 2 thoughpossessing a structure which would appear not to provide developingactivity, is virtually as effective as a developing agent as6,7-dihydroxy-4-methyl coumarin.

EXAMPLE 4 Similar results are obtained as in example 1 employing one ofthe following compounds:

8-Hydroxycoumarin EXAMPLE 5 5-Hydroxy-2-coumaranone EXAMPLE 65-Hydroxy-3-phenyl-2-coumaranone EXAMPLE 75-Hydroxy-6-octyl-2-coumaranone EXAMPLE 8 7-Hydroxy-2-coumaranoneEXAMPLE 9 6-Hydroxy-2-ketol ,4-benzoxathian EXAMPLE l07,8-Dihydroxy-3-methyl-3,4-dihydrocoumarin EXAMPLE ll7,8-Dihydroxy-4-methylcoumarin in place of 7-methyl-6-hydroxy coumarin.

R: Bi

I Ra

wherein:

a. R and R are individually selected from the group consisting ofhydrogen, halogen and alkyl containing one to five carbon atoms;

. R and R are individually selected from the group consisting ofhydrogen, alkyl containing one to five carbon atoms, alkoxy containingone to five carbon atoms, halogen and aryl containing up to 20 carbonatoms; and

. R and R, are individually selected from the group consisting ofhydroxy, amino, hydrogen, alkyl containing one to five carbon atoms,alkoxy containing one to five carbon atoms and aryl containing up to 20carbon atoms; mixtures thereof and their salts; and wherein at least oneof R and R is hydroxy or amino.

2. An element as in claim 1 also comprising a photographic silver saltlayer.

3. An element as in claim 1 also comprising a second silver halidedeveloping agent.

4. An element as in claim 1 wherein said silver halide developingcomponent is [3,4-dimethyl-2,S-dihydroxy cinnamic acid.

5. A photographic element comprising a support, photographic silverhalide and 2,5-dehydroxy cinnamic acid or 2- hydroxy-S-amino cinnamicacid silver halide developing agent.

6. A photographic-processing composition comprising an alkalinedevelopment activator and a 2,5-dihydroxy cinnamic acid or a2-hydroxy-5-amino cinnamic acid silver h .lide developing agent.

7. A photographic-processing composition as in claim 6 also comprising asilver halide solvent.

8. A photographic-processing composition as in claim 6 also comprising asecond silver halide developing agent.

9. A photographic-processing composition as in claim 6 wherein saidsilver halide developing agent is an auxiliary developing agent.

10. A photographic-processing composition as in claim 6 wherein the pHof the developer composition is about 10 to about 14.

11. A photographic processing composition as in claim 6 wherein saidsilver halide developing agent is present in a concentration of 0.0] to10 percent by weight of said processing composition.

12. A photographic processing composition comprising an alkalinedevelopment activator and a coumarin developing agent precursor of theformula:

wherein:

a. R and R, are individually selected from the group consisting ofhydrogen, halogen, and alkyl containing one to five carbon atoms;

b. R and R are individually selected from the group'consisting ofhydrogen, alkyl containing one to five carbon atoms, alkoxy containingone to five carbon atoms, halogen and aryl containing up to 20 carbonatoms; and

c. R, and R are individually selected from the group consisting ofhydroxy, amino, hydrogen, alkyl containing one to five carbon atoms andaryl containing up to 20 carbon atoms; salts of such coumarin compounds;mixtures thereof; and wherein at least R is hydroxy or amino.

14. A photographicprocessing composition comprising an alkalinedevelopment activator and B,4-dimethyl-2,5- dihydroxy cinnamic acid. A

15. A photographic emulsion comprising a photographic silver salt and alactone derivative silver halide developing agent which is selected fromthe group consisting of cinnamic acid developing agents of the formula:

wherein:

a. R and R are individually selected from the group consisting ofhydrogen, halogen, and alkyl containing from one to five carbon atoms;

b. R and R are individually selected from the group consistlng ofhydrogen, alkyl containing one to five carbon atoms, alkoxy containingone to five carbon atoms, halogen and aryl containing up to 20 carbonatoms; and

c. R and R are individually selected from the group consisting ofhydroxy, amino, hydrogen, alkyl containing one to five carbon atoms,alkoxy containing one to five carbon atoms and aryl containing up to 20carbon atoms; salts of such compounds; mixtures thereof and wherein atleast one of R and R is hydroxy or amino.

16. A photographic emulsion as in claim 15 wherein said silver halidedeveloping agent is present in a concentration of 0.01 to 5 moles ofsaid developing agent per mole of said photographic silver salt.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 5Dated ctober 26L 1971 Inventor) Edwin N. Oftedahl Jr.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

r- In Column 3 line 68 "accordingly" should read :1

according-"p In Column 4, line 26, after are as-- should be inserted.

In Column 4, line 55, that part of formula reading "=COOH" should readCOOH In Column 5, line 35, after "6-hydroxy-S,7-dimethoxy" should beinserted -coumarin;--.

In Column 5, line 43, '6-amino" should read 6- hydroxy-.

In Column 5, line 67, "R should be deleted.

In Column 6, line 20, "agents" should read ---agent precursors---.

In Column 6, line 24, "agent precursors" should read --agents (12/10/70amendment, page 1, under IN THE SPECIFICA TION; the Patent Officeerroneously amended line 5 instead of line 9) In Column 6, line 54, "An"should read Any- In Column 7, line 38, that part of formula reading"dimethy" should read dimethyl- In Column 7, line 60, after "coumarins",should be inserted.

In Column 7, line 70, "sliver" should read silver Po-1o50 UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Dated October 26, 1971 Patmu No.,521

Inventr(s) N. Oftedahl, Jr.

in the above-identified patent It is certified that error appearscorrected as shown below:

and that said Letters Patent are hereby F- In Column 8,

---terephthalate--.

line 30, "terephthanlate" should read In Column 9, line 19, after"Russell", should be inserted.

In Column 12, line 2, "variable" should read variables.

In the Claims:

In Column 15, line 11, after "five carbon atoms" should be insertedalkoxy containing 1 to 5 carbon atoms (12/10/70 amendment, page 2, Claim46(c) Signed and sealed this 5th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. Attesting Officer ROBERT GOTTSCHALK Commissionerof Patents

2. An element as in claim 1 also comprising a photographic silver saltlayer.
 3. An element as in claim 1 also comprising a second silverhalide developing agent.
 4. An element as in claim 1 wherein said silverhalide developing component is Beta ,4-dimethyl-2,5-dihydroxy cinnamicacid.
 5. A photographic element comprising a support, photographicsilver halide and 2,5-dihydroxy cinnamic acid or 2-hydroxy-5-aminocinnamic acid silver halide developing agent.
 6. Aphotographic-processing composition comprising an alkaline developmentactivator and a 2,5-dihydroxy cinnamic acid or a 2-hydroxy-5-aminocinnamic acid silver halide developing agent.
 7. Aphotographic-processing composition as in claim 6 also comprising asilver halide solvent.
 8. A photographic-processing composition as inclaim 6 also comprising a second silver halide developing agent.
 9. Aphotographic-processing composition as in claim 6 wherein said silverhalide developing agent is an auxiliary developing agent.
 10. Aphotographic-processing composition as in claim 6 wherein the pH of thedeveloper composition is about 10 to about
 14. 11. A photographicprocessing composition as in claim 6 wherein said silver halidedeveloping agent is present in a concentration of 0.01 to 10 percent byweight of said processing composition.
 12. A photographic processingcomposition comprising an alkaline development activator and a coumarindeveloping agent precursor of the formula:
 13. A photographic-processingcomposition as in claim 12 wherein said developing agent precursor ispresent in a concentration of 0.01 to 10 percent by weight of saidprocessing composition.
 14. A photographic processing compositioncomprising an alkaline development activator and Beta,4-dimethyl-2,5-dihydroxy cinnamic acid.
 15. A photographic emulsioncomprising a photographic silver salt and a lactone derivative silverhalide developing agent which is selected from the group consisting ofcinnamic acid developing agents of the formula:
 16. A photographicemulsion as in claim 15 wherein said silver halide developing agent ispresent in a concentration of 0.01 to 5 moles of said developing agentper mole of said photographic silver salt.